In a letter to Warner Bros., family members of victims of the 2012 mass shooting during a screening of “The Dark Knight Rises” at an Aurora, Colo., theater, expressed worries about the upcoming “Joker” film. They’re asking the entertainment studio to donate to gun-victim organizations and advocate for gun reform.

“When we learned that Warner Bros. was releasing a movie called ‘Joker’ that presents the character as a protagonist with a sympathetic origin story, it gave us pause,” says the letter, which was obtained by Variety. It was sent Tuesday to Warner Bros.’ new CEO, Ann Sarnoff, and was signed by several family members.

Set for release Oct. 4, director Todd Phillips’ dark, gritty and widely anticipated comic book adaptation starring Joaquin Phoenix has sparked controversy for the film’s violence in a time of increasing mass shootings.

The Hollywood Reporter reported Tuesday that the Aurora theater where the mass shooting happened will not be showing the film, citing a theater employee.

The families clarified that they’re not calling for the movie’s ban or boycott, writing, “We support your right to free speech and expression. But as anyone who has ever seen a comic book movie can tell you: with great power comes great responsibility. That’s why we’re calling on you to use your massive platform and influence to join us in our fight to build safer communities with fewer guns.”

Instead, the letter said: “We are calling on you to be a part of the growing chorus of corporate leaders who understand that they have a social responsibility to keep us all safe.”

A rep for Warner Bros. did not immediately respond to The Times’ request for comment.

On July 20, 2012, a masked gunman killed 12 people and injured 70 when he entered a Colorado movie theater screening of “The Dark Knight Rises.” Police said James Holmes, who reportedly identified as the Joker, was armed with a rifle, a shotgun and two handguns.

Among the letter’s signers were Lonnie and Sandy Phillips, whose daughter Jessica Ghawi was killed in the shooting. They teamed up with Igor Volsky, director of the gun-control advocacy nonprofit Guns Down America, to draft the letter.

The families are also asking Warner Bros. to cease political contributions to candidates who accept money from the NRA and oppose gun reform; use its political influence to lobby Congress for gun reform; and give money to gun violence intervention programs.

“Since the federal government has failed to pass reforms that raise the standard for gun ownership in America, large companies like Warner Brothers have a responsibility to act,” the letter says. “We certainly hope that you do.”